Inferior and inferior-lateral location of left ventricular dyssynergy after myocardial infarction begets ischemic mitral regurgitation.

Introduction: Ischemic mitral regurgitation (IMR) after myocardial infarction (MI) results from changes in left ventricular geometry, which may involve the entire ventricular cavity (global remodeling) or predominantly affect the infarct zone (regional remodeling). The relative importance of these two distinct but not mutually exclusive mechanisms in generating IMR has been a matter of debate. The aim of our study was to assess the relative contribution of global versus inferior and inferior-lateral left ventricular dyssynergy in the development of significant IMR after MI. Methods: We retrospectively studied 40 consecutive patients (24 male, age 68±11 years) with previous MI and significant IMR evaluated by Doppler study. This group was compared with a control group of 40 consecutive patients (38 male, age 64±11 years) with previous MI but no significant IMR. Echocardiographic assessment of ventricular volumes and global and regional wall motion indices was performed in both groups. Results: A higher proportion of female patients was found in the group with IMR. There were no significant differences in other demographic or cardiovascular characteristics and risk factors. Left ventricular ejection fraction was reduced in both groups, but was significantly lower in the group with IMR (34±8% vs. 39±9%, p=0.024). Although end-diastolic volumes and global wall motion scores were similar in the two groups, different patterns of regional dyssynergy were found. The degree of inferior and inferior-lateral regional dyssynergy was the main determinant of significant IMR. Conclusions: Inferior and inferior-lateral left ventricular dyssynergy appears to be more important than global systolic dysfunction in the development of significant ischemic mitral regurgitation. Closer clinical and echocardiographic follow-up is warranted in post-MI patients presenting dyssynergy in this location.